Inkjet printers and related inkjet devices have proven to be reliable, efficient, and generally cost effective means for the accurate delivery of precisely controlled amounts of ink and other related liquid materials onto various substrates such as, but not limited to, glass, paper, cloth, transparencies and related polymer films. For example, modern inkjet printers for consumer market digital printing on paper offer printing resolutions in excess of 2400 dots per inch (DPI), provide printing speeds greater than 60 sheets per minute, and deliver individual droplets of ink in a ‘drop-on-demand’ method that are often measured in picoliters. The relatively low costs, high print quality and generally vivid color output provided by these modern inkjet printers has made these printers among the most common digital printers in the consumer market.
Currently, in addition to the consumer market, there is considerable interest in employing inkjet printing for high-speed commercial and industrial applications. Among the chief challenges of the high-speed commercial and industrial printing markets are high throughput, large format substrates, and high reliability (or a related parameter, high duty cycle). Such high-speed commercial and industrial inkjet printers often employ multiple printheads working in parallel. The multiple printheads are often arranged in an array and may be implemented as a print bar that spans a width of the print substrate, for example.
High-speed commercial and industrial applications often demand high-speed data channels for communicating print data to the printheads. For example, data rates in excess of hundreds of megahertz (MHz) to one or more gigahertz (GHz) may be used. With the use of such high-speed data channels, there is typically a need for verifying a performance of the high-speed data channels. In addition, the high-speed nature of, and more particularly high clock frequencies used in conjunction with, the high-speed data channels may place tight constraints on data timing within and between the printheads of the printer. As such, there is also often a need for calibrating and potentially adjusting time delays associated with the high-speed data channels to insure that data sent to the printheads is received properly.
Unfortunately, economic pressure to generally lower costs of printheads in these high-speed commercial and industrial inkjet printers typically leads to a reduction in a number of input and output (I/O) connections at the printheads. Reducing I/O connections usually means a reduction in or even complete elimination of I/O connections dedicated to testing the printheads.
Certain examples have other features that are one of in addition to and in lieu of the features illustrated in the above-referenced figures. These and other features are detailed below with reference to the preceding drawings.